This invention relates to a method of establishing a voice/data call over a voice/data channel as set forth in the preamble of the main claim.
In existing telephone networks, a subscriber establishes a connection to another subscriber in which the service used is predefined. It is not possible for the subscriber to select the type of connection, such as a standard connection or a connection to a voice mailbox, prior to the establishment of the connection. The subscriber either is forced to dial a specific number in order to get his specific call request executed, or he can indicate his request during the call by signaling. In either case, the subscriber will already have established a connection, either to another terminal or to a switching unit. It is not possible for the subscriber to indicate to the network that he wants a specific execution of his call request as long as the connection is not established. It is known to implement a call-screening function in which a center of the network receives the incoming number and compares it with stored data. This method makes it possible to carry out different service actions prior to the establishment of a call. The center checks the incoming number to determine, for example, whether the called subscriber wants to accept this call. This check takes place at the center and must be applied for by the subscriber and installed by the network operator in advance.
Another solution is described in U.S. Pat. No. 5,544,236. Here the subscriber, by dialing a specific number, is connected to a processor which is capable of selecting different service features for a connection. The processor offers several possibilities, and the subscriber can interactively select the service he desires for the call to be established. When the specific number is dialed, the subscriber is connected to the processor. A connection is thus established, i.e., the subscriber incurs costs for the establishment of the connection. The different service features can be selected by keypad or voice entries.